By Dharmananda Sarangi and Bidur Kant Jha
Building a robust and resilient road infrastructure is essential for long term socio-economic development of the country. Road infrastructure is required to provide faster mobility together with safety, logistic efficiency and user conveniences and it should also be sustainable in the long run. Conventionally, road construction is associated with depletion of natural resources such as stone, fertile soil, sand, etc., felling of trees, emission of green-house gases, etc. Resolving these trade-offs are essential to achieve sustainable development.
To cite one example, one lane-km of road construction requires 20,000 ton (approx.) of good quality stones. Further, it is estimated that construction of every lane-km of NH generates CO2 emissions[1] to the tune of 24–30 tonne per year. Under PM Vision for Green Future & Net Zero, India has set ambitious targets of achieving ”net zero” by 2070. Therefore, to conserve the limited reserves of natural resources as well as minimize emission of greenhouse gases, MoRTH (Ministry of Road Transport and Highways) under the visionary leadership of Hon’ble Prime Minister and able leadership of Hon’ble Minister, Road Transport & Highways has strategized its planning, design, construction and maintenance of highways based on the following principles:
- Optimization of design using new materials, processes and technology resulting in material savings, longer life, accelerated construction,
- Minimize consumption of natural resources
- Focus on locally available materials
- Use of eco-friendly alternate material
- Reduce, reuse and recycle of waste materials
- Conservation of water, soil, flora & fauna,
- Adoption of green construction practices
- Use of efficient and environmental friendly construction equipment and machineries
- Conservation of energy
- Landscaping and plantation
- Prevention and control of emission of GHGs, water pollution, ambient noise level, soil erosion & pollution, handling and disposal of volatile, solid & liquid waste
- Evaluation based on life-cycle costing
A few landmark achievements in use of such materials, technology, processes in different National Highway projects to bring about sustainable development can be summarised as under:
- Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) for long span bridge (65 Nos. of bridges constructed / under construction with UHPFRC).
- Processed Steel Slag-(2.6 million MT used)
- Waste Plastic in bituminous mixes (2830km road constructed)
- Inert material of Municipal Landfill (2.4 million MT used)
- Bamboo Crash Barrier (8.5 km)
- Transplantation of uprooted trees (70,000 )
- Materials/technology such as soil stabilisation, precast concrete elements, high performance bituminous mixes, various types of geosynthetics, natural mats like coir/jute, recycle of existing bituminous pavements, full depth reclamation, reuse of tunnel mg/landslide materials, use of construction & demolition waste, bio-bitumen, fiber reinforced polymer rebars in replacement of steel bars for reinforced concrete, etc. are being used in different NH projects to varying
Typically, 135 km long Eastern Peripheral Expressway developed by NHAI can be considered as a model case for green highway project as it minimizes carbon footprint in manifold ways:
- Generation of Solar Power: Capacity of 4 MW
- Drip Irrigation for plants
- Rain water harvesting has been provided at every 500 m
- About 12 million cum of fly ash has been
- Extensive plantation: 6 lakh trees planted
Green National Highways Corridor Projects (GNHCP) being implemented with assistance of World Bank is also another example of use of sustainable technologies. Seven stretches of National Highways involving 23 construction packages having total length of 783 km have been taken up under GNHCP. Green materials/technology such as coir/jute mat, hydroseeding, interlinked chain mesh with green strips, bamboo plantation, vetiver grass, hedge brush layering, recycling, etc. are being used in the said project.
MoRTH has been continuously striving to evaluate the performance of such materials and technology measures in terms of saving in carbon footprints, strength, durability and serviceability. While the performance of materials, processes, technology now being used or attempted to use need to be consolidated, continued efforts are being made to identify and develop new ones in a committed manner.
[1] Report of TERI
The authors Dharmananda Sarangi is Director General (Road Development) and Special Secretary in Ministry of Road Transport and Highways.
And Bidur Kant Jha is Director (New Technology) in Ministry of Road Transport and Highways
-PIB
